This invention relates generally to interlocking telescoping members and, more particularly, has particular applicability to invalid devices having interlocking telescoping members.
Interlocking telescoping members are conventionally used in a plurality of different fields for different applications. Generally, an inner telescoping member is slidably received within an outer telescoping member having a plurality of longitudinally aligned apertures therein. A button device is associated with the inner telescoping member and may, for example, extend through an aperture in the inner telescoping member for engagement with one of the longitudinally aligned apertures in the outer telescoping member. To this end, a spring positioned within the inner telescoping member outwardly biases the button for engagement with one of such apertures. Examples of such arrangements are shown in U.S. Pat. No. 3,947,140 and French Pat. No. 1,040,848.
To adjust the height, length or the like of a device, the button is depressed inwardly against the force of the spring and the inner telescoping member is slidably moved within the outer telescoping member until the button is aligned with another aperture in the outer telescoping member, whereupon the spring outwardly biases the button into engagement therewith to lock the inner and outer telescoping members in a fixed relation. However, when the user presses the button inwardly against the spring and then, while the button is depressed, slidably moves the inner telescoping member with respect to the outer telescoping member, there is a tendency for the telescoping members to pinch the finger of the user during the initial sliding movement between the telescoping members.
In U.S. Pat. No. 4,056,115, the problem of pinching was solved by providing a plunger arrangement to depress the button inwardly against the force of the spring. The plunger arrangement, however, is relatively complicated and it would be impractical to use a plurality of such plunger arrangements where a plurality of longitudinally aligned apertures are provided in the outer telescoping member. Alternatively, it would be impractical to slide a single plunger arrangement along the outer telescoping member where a plurality of apertures are provided therein.
When the aforementioned telescoping arrangement is used with an invalid device, such as a cane, there is the further problem of rattling between the inner and outer telescoping members each time that the cane is hit upon the ground. Attempts have been made in the prior art to overcome such undesireable rattling problem by providing a set screw in place of or in addition to the button arrangement, for example, as disclosed in U.S. Pat. No. 4,085,763, or by providing a knurled locking nut at the lower end of the outer telescoping member. However, the use of a set screw makes it difficult to adjust the telescoping members. Further, the knurled locking nut or collar arrangement is not entirely effective against rattle.